diff options
| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2007-11-20 11:13:36 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2007-11-20 11:13:46 +0100 |
| commit | ce7e9fae8db07af4080e868f4588f8f095f803dc (patch) | |
| tree | 000a6cc755ee35ef3cfc0795c13ed500dc5457de /mm | |
| parent | b8e7a54cd06b0b0174029ef3a7f5a1415a2c28f2 (diff) | |
[S390] Optimize storage key handling for anonymous pages
page_mkclean used to call page_clear_dirty for every given page. This
is different to all other architectures, where the dirty bit in the
PTEs is only resetted, if page_mapping() returns a non-NULL pointer.
We can move the page_test_dirty/page_clear_dirty sequence into the
2nd if to avoid unnecessary iske/sske sequences, which are expensive.
This change also helps kvm for s390 as the host must transfer the
dirty bit into the guest status bits. By moving the page_clear_dirty
operation into the 2nd if, the vm will only call page_clear_dirty
for pages where it walks the mapping anyway. There it calls
ptep_clear_flush for writable ptes, so we can transfer the dirty bit
to the guest.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/rmap.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index dc3be5f5b0da..dbc2ca2057a5 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -471,11 +471,12 @@ int page_mkclean(struct page *page) if (page_mapped(page)) { struct address_space *mapping = page_mapping(page); - if (mapping) + if (mapping) { ret = page_mkclean_file(mapping, page); - if (page_test_dirty(page)) { - page_clear_dirty(page); - ret = 1; + if (page_test_dirty(page)) { + page_clear_dirty(page); + ret = 1; + } } } |